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In several articles, I've mentioned the need to brine chicken or pork to produce juicier, more flavorful, and tender cooked meats. The net effect of brining is to infuse the meat with extra salt (and sometimes sugar and other flavorings) and water. But how does brining work? In this article, I examine what happens when you brine.

What does brining do?Brining is the soaking of meat in a solution of water and salt. Additional flavorings like sugar and spices can also me added, but salt is what makes a brine a brine (just like acid makes a marinade a marinade). This soaking causes the meat to gain some saltiness and flavoring while plumping it up with water so that after cooking it still contains a lot of juices.

The explanation for why brining works that I hear most often is that by surrounding the meat with salt water, salt and water are forced into the tissue through osmosis. Unfortunately, I've never been happy with that explanation. Osmosis is when a solvent (usually water or other liquid that can hold another substance, called the solute, in solution - like salt) moves from a low solute concentration (like the tissue of the meat) to a high solute concentration (like the salt water) through a semipermeable membrane (a surface that allows small particles to pass but not larger ones - like the cell membranes of our chicken or pork) to form an equilibrium. Hmmm... wait a minute. If that's true then water will be drawn from the low salt concentration meat to the high salt concentration salt water. At the same time, if the salt can enter the meat (which it can), then salt will be moving from salt water to meat. Won't that result in a salty, dry piece of poultry or pork?

Obviously, there's more going on than simple osmosis. It is true that salt enters the meat (it tastes more salty after brining). But why is it also more juicy? Well, when water flows out of the meat, salt flows in and begins to break down some of the proteins in the cells. In the broken down state, the molecules become more concentrated and the solute levels rise within the meat. This causes additional water to flow into the meat.

But doesn't that mean we've got the same amount of water as before brining? Nope. The cell membranes are semipermeable. They allow salt and water to flow in both directions freely, but larger molecules (like the denatured proteins and other solutes in the meat released by the salt) cannot flow out from within the cells. When the solutes of a solution on one side of a semipermeable membrane cannot pass to the other side, osmosis causes more and more solvent to move through the semipermeable membrane. This continues until the extra pressure from holding more solvent equals the rate at which solvent is "drawn" through the semipermeable membrane. (This rate is called osmotic pressure. How Stuff Works has a short article describing osmotic pressure with a diagram that may be helpful to visualize the water flow.)

What has happened is that through brining, we've caused a state change in the cells so that they will draw and hold more water than before. As we cook the meat, the heated proteins will begin to draw in tighter and squeeze out water, but, hopefully, enough water will remain to produce a juicy, tender piece of meat.

Brining SolutionSo, how much salt in water is used for brining? That really depends on how long of a brine you want and how salty you want the final product. A weak brine will require a longer brining time to achieve the same saltiness as a strong brine. When I need a moderate strength brine, I use 1/2 cup (about 150 g) of table salt per gallon of water. (Higher concentrations of salt can be used to reduce brining times, but the amount of salt and the time it takes to brine is dependent on the muscle structure of the particular piece of meat.) Using kosher salt is a common practice, but different manufacturers grind the salt to different levels of coarseness, so kosher salt should be weighed before adding to water. For small amounts of salt, the salt can be dissolved into cold water, but for larger quantities it may be necessary to heat the water to dissolve the salt.

Brining TimeAlways start with a cold brine. If you heated the brine, then refrigerate it before using it. The raw meat will be in the brine for a number of hours, so we don't want the temperature of the meat to rise higher than refrigerator temperatures (40°F, 4°C) if we can help it. Place the brine in a noncorrosive container like a plastic or glass container, plastic bag, or a stainless steel pot.

The brining time depends on the shape of your meat as well as the type of meat. Generally, a good rule of thumb is 2 hours per pound of solid poultry when using the 1/2 cup salt per gallon brine. Cut up poultry will have reduced brining time. For chicken pieces like breasts or thighs, 2 hours is usually enough time. Pork may take about four times as long to brine as poultry. In most cases, it's difficult to predict how fast the salt moves into the meat when you double or halve the salt in the brine, but it's worth experimenting with to have your brining "finish" at a time where you will be around to remove the meat from the brine.

When you remove the meat from the brine, rinse off the excess salt from the surface and return the meat to the refrigerator to await cooking. Pour out the brine after each brining. (No need to have a half gallon of raw meat juice infused salt water lying around growing germs...)

Just a quick question. Is this procedure basicaly the same for Brining Olives ? I have a few olives trees and they are fruiting rather splendidly after a bit of judicious pruning and what do you know I have a few kilos too play with.

It is possible to bring olives in a similar fashion. Use salt that is uniodinized and dissolve about 1/2 cup for each gallon of water. You probably won't need much water, so reduce the salt by the proportional amount.

Brining olives usually takes weeks. You'll probably need something to keep the olives under the salt water during the brining. Also, stir the olives once a week. After three or four weeks, the bitter taste of the olives should have reduced and they are considered brined or cured.

And what happens if you brine too long -- e.g. if I put the chicken in brine in the morning and take it out when I get home 9 hours later?

If you brine too long, all that happens is that the meat becomes too salty. In most cases, it's difficult to brine the meat so much that it becomes unpalatable. If you do plan on having a longer brine, reduce the salt concentration in the water. Start by halving the concentration if you plan to double the brining time. This doesn't work perfectly, but is a good starting point. If the meat's not salty enough, then next time increase some salt content in the solution.

Great explanation Michael. One comment - you imply to use non-iodized salts - I would like to emphasize the point that for brining, whether meats or for pickling, only use non-iodized salts, i.e. kosher or canning salt. Iodized salts imparts metallic flavors and will darken pickled vegetables.

Regarding olives - I ran across the following site:
http://www.oliveoilnews.com/olive_recipes_.htm
I was going to try curing olives this fall but never got around to it. I have brined pickles and the proportions are similar as to what Michael recommends, however the chemistry is different. For vegetables, the brining promotes lacto-fermentation, which preserves and flavors.

How salty is the meat? I don't really like salty food (I add it to get some flavour, but I don't actually like a salty flavour). Would you recommend not adding extra salt to the dish if I wanted to avoid it being too salty?

When brined properly, the saltiness is just a bit less than if you salted the meat after cooking. Except, the salt will be distributed throughout the meat instead of clumped on the surface. You can attempt to reduce the saltiness by using less salt in the brine and brining for a slightly longer duration. Make sure you rinse off the meat after brining and pat dry.

I would suggest not adding additional salt if you dislike the flavor of salt. For almost all dishes, I would recommend at least reducing the salt that would have otherwise been added.

If I remember chemistry 101, you're correct in your assupmtion that osmosis doesn't explain why brining works. One aspect that wasn't noted in the article is the basic reaction of salt on proteins, e.g. that salt denatures proteins, making them unbind and form looser bonds (that's why you can't add salt to the liquid in which you poach eggs).

I'd bet that the salt in the brininig solution helps to denature the proteins in meat, changing the osmotic properties of the cells, and allowing for a freer transfer of liquids (and flavorings).

You mention that if you had to heat up your brining solution, you should then refrigerate it to cool it down. Just thought I'd point out that putting a laarge container of hot water in your fridge is going to raise the temperature of your fridge, possibly into the prime bacterial growth range. Instead of popping it in the fridge, I'd recommend putting in the sink and surrounding it with ice to cool it down a bit.

What about open grained meats like porkchops? I've had good luck with chicken breasts at a two hour soak, but I'm afraid of oversalting the chops.Also,if using herbs in the brine, how much is actualy absorbed?
I'm an EE not a chemist.